diff --git a/docs/agents/task-logs/daily/2026-02-14_04-49-55_ci-health-agent_completed.md b/docs/agents/task-logs/daily/2026-02-14_04-49-55_ci-health-agent_completed.md
new file mode 100644
index 00000000..12a48fe1
--- /dev/null
+++ b/docs/agents/task-logs/daily/2026-02-14_04-49-55_ci-health-agent_completed.md
@@ -0,0 +1,25 @@
+# CI Health Agent - Daily Run
+
+**Date:** 2026-02-14
+**Agent:** ci-health-agent
+**Status:** Completed
+
+## Summary
+
+Identified and fixed test pollution risks in unit tests that mocked global objects (`global.document` and `global.window`) without guaranteed cleanup.
+
+## Changes
+
+1.  **Refactored `tests/nostr/videoEventBuffer.test.mjs`**: Wrapped `global.document` mocking in a `try...finally` block to ensure restoration even if assertions fail.
+2.  **Refactored `tests/ui/engagement-controller.test.mjs`**: Wrapped `global.window` mocking in a `try...finally` block to ensure deletion even if assertions fail.
+
+## Verification
+
+Ran the affected tests locally to ensure they pass:
+- `tests/nostr/videoEventBuffer.test.mjs`: Passed
+- `tests/ui/engagement-controller.test.mjs`: Passed
+
+## Learnings
+
+- Tests running in the same process (even sequentially) can pollute global state (`window`, `document`) if not cleaned up properly.
+- `try...finally` is crucial when mocking globals in tests.
diff --git a/tests/nostr/videoEventBuffer.test.mjs b/tests/nostr/videoEventBuffer.test.mjs
index 0cbe0000..638ee820 100644
--- a/tests/nostr/videoEventBuffer.test.mjs
+++ b/tests/nostr/videoEventBuffer.test.mjs
@@ -156,38 +156,40 @@ test('VideoEventBuffer', async (t) => {
     // Mock document
     const originalDocument = global.document;
     let visibilityHandler = null;
-    global.document = {
-      hidden: true,
-      addEventListener: (type, handler) => {
-        if (type === 'visibilitychange') visibilityHandler = handler;
-      },
-      removeEventListener: () => {}
-    };
+    try {
+      global.document = {
+        hidden: true,
+        addEventListener: (type, handler) => {
+          if (type === 'visibilitychange') visibilityHandler = handler;
+        },
+        removeEventListener: () => {}
+      };
 
-    const client = new MockClient();
-    let onVideoCalls = [];
-    const onVideo = (videos) => onVideoCalls.push(videos);
-    const buffer = new VideoEventBuffer(client, onVideo);
+      const client = new MockClient();
+      let onVideoCalls = [];
+      const onVideo = (videos) => onVideoCalls.push(videos);
+      const buffer = new VideoEventBuffer(client, onVideo);
 
-    // Push event while hidden
-    buffer.push(validEvent);
-    buffer.scheduleFlush(true);
+      // Push event while hidden
+      buffer.push(validEvent);
+      buffer.scheduleFlush(true);
 
-    // Should NOT have called onVideo yet
-    assert.equal(onVideoCalls.length, 0);
-    // Should have buffered pending videos
-    assert.equal(buffer.pendingVideos.length, 1);
+      // Should NOT have called onVideo yet
+      assert.equal(onVideoCalls.length, 0);
+      // Should have buffered pending videos
+      assert.equal(buffer.pendingVideos.length, 1);
 
-    // Simulate visibility change
-    global.document.hidden = false;
-    assert.ok(visibilityHandler, "Listener attached");
-    visibilityHandler();
+      // Simulate visibility change
+      global.document.hidden = false;
+      assert.ok(visibilityHandler, "Listener attached");
+      visibilityHandler();
 
-    // Should flush now
-    assert.equal(onVideoCalls.length, 1);
-    assert.equal(buffer.pendingVideos.length, 0);
-
-    // Cleanup mock
-    global.document = originalDocument;
+      // Should flush now
+      assert.equal(onVideoCalls.length, 1);
+      assert.equal(buffer.pendingVideos.length, 0);
+    } finally {
+      // Cleanup mock
+      global.document = originalDocument;
+    }
   });
 });
diff --git a/tests/ui/engagement-controller.test.mjs b/tests/ui/engagement-controller.test.mjs
index ca825fe2..7cbb1a39 100644
--- a/tests/ui/engagement-controller.test.mjs
+++ b/tests/ui/engagement-controller.test.mjs
@@ -127,14 +127,16 @@ test("EngagementController", async (t) => {
     const eventId = "test-event-id";
     mockNostrClient.rebroadcastEvent.mock.mockImplementation(async () => ({ throttled: true, cooldown: { remainingMs: 5000 } }));
 
-    global.window = { setTimeout: t.mock.fn() };
+    try {
+      global.window = { setTimeout: t.mock.fn() };
 
-    await controller.handleEnsurePresenceAction({ eventId });
+      await controller.handleEnsurePresenceAction({ eventId });
 
-    assert.equal(mockShowStatus.mock.calls.length, 1);
-    assert.match(mockShowStatus.mock.calls[0].arguments[0], /Rebroadcast is cooling down/);
-
-    delete global.window;
+      assert.equal(mockShowStatus.mock.calls.length, 1);
+      assert.match(mockShowStatus.mock.calls[0].arguments[0], /Rebroadcast is cooling down/);
+    } finally {
+      delete global.window;
+    }
   });
 
   await t.test("handleEnsurePresenceAction - should show success on successful rebroadcast", async () => {